Modulating Transformer Primary to Control Secondary Power Output

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Joined Apr 28, 2011
I have an application where I will be controlling a resistive load in a closed loop. The load is connected to the secondary coil of a transformer. The transformer primary needs to be switched to control the power output. My system needs to be extremely responsive because it will reach temperature very fast, anywhere from 400 - 1000 ms depending on the configuration. I have come across info that says zero-cross switching is bad for controlling transformers due to the inrush current. A lot of info has pointed to Triac or Thyristors for Phase-Angle control. Is there a definitive go-to solution for this type of control? Would my controls be responsive enough just peak-switching at 60Hz periods, or would I need a phase-angle control?

Some info I know from a similar application that I am trying to mimic:
Resistive load has a linear relation to heat vs resistance
Current through load as well as voltage across load is measured at 60Hz sample rate
The system heats up no more than 1deg C/ms
System starts at or near 100% power output on startup but settles around 25% power output while in operation, which should last a few seconds.